The effect of tranexamic acid on blood loss in orthognathic surgery: a randomized,placebo-controlled,equivalence study

Orthognathic surgery can cause substantial bleeding. Recent meta-analyses concluded that there is a statistically significant reduction in perioperative blood loss with the preventive use of tranexamic acid (TA). However, the mean reported difference in bleeding was moderate, and the clinical relevance of this blood-sparing effect remains debated. We therefore conducted a prospective, double-blind, randomized, placebo-controlled equivalence study of the effect of TA in patients undergoing Lefort I or bimaxillary osteotomies. Our main outcome measure was total blood loss on postoperative day 1. The equivalence margin was ± 250 ml for the difference in blood loss and its 95% confidence interval. One hundred and forty-seven patients were randomized, of which 122 underwent bimaxillary osteotomies. Blood loss in the treatment group was 682 ± 323 vs. 875 ± 492 ml. The mean difference in bleeding was -132 [-243; -21] ml as per-protocol, but -193 [-329; -57] ml in intention-to-treat: the limits of this confidence interval exceeded the margin of equivalence. Similar results were obtained when analysing only patients undergoing bimaxillary osteotomy. Haemoglobin decreased by 1.8 ± 1.2 g/dl with TA, vs. 2.6 ± 1.1 g/dl with placebo (p<0.001). Our study did not demonstrate equivalence between TA and placebo on perioperative blood loss in orthognathic surgery. TA may reduce blood loss but without evidence of clinical consequences.     

口服云南白药对正颌外科术中出血量影响的随机双盲对照研究

目的 研究和评价口服云南白药胶囊对正颌外科术中出血量的影响和安全性.方法 将需行Le Fort Ⅰ型截骨术和双侧下颌升支矢状劈开截骨术(bilateral sagittal split ramus osteotomy,BSSRO)的牙.颌.面畸形患者87例根据随机数字表分为A组(43例)和B组(44例),术前3 d开始分别口服云南白药胶囊或安慰剂胶囊,比较分析术中出血量差异并观察用药过程中的安全性.结果 87例患者中,出血总量平均值:A组(330.5±134.4)ml,B组(420.3±175.9)ml,两组出血总量比较,差异有统计学意义(P<0.05).A组Le Fort Ⅰ型截骨术平均出血量(154.9±84.3)ml,B组(203.8±98.1)ml,两组比较差异有统计学意义(P<0.05).A组BSSRO平均出血量(175.6+81.3)ml低于B组BSSRO平均出血量(216.4±113.8)ml,两组比较差异无统计学意义(P>0.05).两组患者术后纤溶功能检查结果,差异无统计学意义(P>0.05).围手术期未发生不良反应.结论 术前口服云南白药胶囊可有效减少正颌外科术中出血量,同时不会增加血栓形成风险.     

上颌骨缺损患者手术前后咀嚼运动时脑血流的变化研究

目的:测量上颌骨缺损患者手术前后咀嚼运动时脑血流的变化,探讨上颌骨缺损所致咀嚼功能降低与脑血流变化的关系.方法:选取因肿瘤手术切除将导致上颌骨缺损的患者16例,应用经颅多普勒超声探测仪,测量其手术前不咀嚼、空咀嚼5min、10min三个时段的大脑中动脉(MCA)收缩期峰流速(Vs)、舒张期末峰流速(Vd)、平均峰流速值(Vm).在患者手术后约2个月(永久赝复体修复前),再分别测量相应的数值.采用SPSS13.0进行重复测量数据的方差分析.结果:手术因素对于Vs、Vd的影响差异无统计学意义(P＞0.05),而对于Vm有明显的影响(P＜0.05).时间因素对Vs、Vd、Vm的影响差异有统计学意义(P＜0.05).随着咀嚼时间的延长,峰流速均数增加.时间因素与手术因素(即术前和术后)对Vs、Vd、Vm的影响有交互作用(P＜0.05).结论:切除术前和术后,空咀嚼运动均有促使其大脑中动脉脑血流量增加的作用,且随咀嚼运动时间延长(累计咀嚼10min),脑血流速呈加快趋势.与术前相比,切除术后咀嚼运动时大脑中动脉血流量降低.     

Reduction in incidence of methicillin-resistant Staphylococcus aureus (MRSA) after radical surgery for head and neck cancer

This study investigated factors associated with the onset of methicillin‐resistant Staphylococcus aureus (MRSA) infection among patients with head and neck cancer who underwent radical reconstructive surgery. The study group consisted of 103 patients who underwent radical reconstructive surgery between January 1994 to December 2002. They were divided into two groups with respect to the date of surgery: Group I (from January 1994 to December 1997) and Group II (from January 1998 to December 2002). The use of third‐generation cephalosporins and imipenem as postoperative antibiotics was restricted after 1998 (Group II). A significantly lower incidence of MRSA was found in Group II than for Group I (p=0.0069, X² test). The following factors were identified as being associated with the onset of MRSA infection: long surgical duration (p<0.035, Witcoxon signad‐rank test), large hemorrhage (p<0.049, Wilcoxon signed‐rank test), and use of third‐generation cephalosporins or imipenem (p<0.004, X² test). MRSA infection was found more often in the surgically reconstructed tongue and floor of the mouth. The use of antibiotics such as vancomycin, wound irrigation, curettage and sequestrectomy were effective in eradicating the infection. MRSA, when it occurred in the maxilla, was mostly limited to colonization.     

Comparison of gingival blood flow during healing of simplified papilla preservation and modified Widman flap surgery: a clinical trial using laser Doppler flowmetry

AIM: This prospective randomized-controlled clinical trial compared the gingival blood flow responses following simplified papilla preservation (test) versus modified Widman flap (control). MATERIALS AND METHODS: Twenty contra-lateral upper sites with pocket depth > or = 5 mm after initial treatment in 10 chronic periodontitis patients were randomly assigned to either test or control treatment, using a split-mouth design. Laser Doppler flowmetry recordings were performed pre-operatively, following anaesthesia, immediately post-operatively and on days 1, 2, 3, 4, 7, 15, 30 and 60, at nine selected sites per flap. RESULTS: Significant ischaemia was observed at all sites following anaesthesia and immediately post-operatively. At the mucosal flap basis, a peak hyperaemic response was observed on day 1, which tended to resolve by day 4 at the test sites, but persisted until day 7 at the control sites. The buccal and palatal papillae blood perfusion presented the maximum increase on day 7 in both groups and returned to baseline by day 15. Both surgical modalities yielded significant pocket depth reduction, recession increase and clinical attachment gain. CONCLUSIONS: Periodontal access flaps represent an ischaemia-reperfusion flap model. The simplified papilla preservation flap may be associated with faster recovery of the gingival blood flow post-operatively compared with the modified Widman flap.     

Effect of induced hypotensive anaesthesia vs isovolaemic haemodilution on blood loss and transfusion requirements in orthognathic surgery: a prospective, single-blinded, randomized, controlled clinical study

Induced hypotensive anaesthesia and isovolaemic haemodilution are well-established blood-sparing techniques in major surgery. This prospective study compared them for blood loss, transfusion requirements, and surgical field quality during standardized orthognathic operations. In a surgeon-blinded trial, 60 healthy patients requiring either Le Fort I osteotomy or bimaxillary surgery were randomly allocated to receive normotensive anaesthesia, induced hypotensive anaesthesia, or induced hypotensive anaesthesia combined with isovolaemic haemodilution. Blood loss and haemoglobin level were measured intraoperatively and calculated on postoperative day 3. The surgeons rated surgical field quality. Mean blood loss was 1021.63, 392.38 (p<0.05) and 1191.65ml in the normotensive, hypotensive and haemodilution groups, respectively. Mean haemoglobin level immediately after surgery was 9.3, 10.3, and 7.4g/dl (p<0.05), respectively. No hypotensive group patients received transfusions; four normotensive group patients required allogenic transfusions; seven haemodilution group patients needed autogenous retransfusions (p<0.05). Surgical field quality was significantly better in the hypotensive than in the normotensive (p<0.05) or haemodilution (p<0.05) groups. In orthognathic surgery, hypotensive anaesthesia significantly reduces blood loss and transfusion requirements and minimizes allogenic transfusions risks. Induced hypotensive anaesthesia combined with isovolaemic haemodilution has no additional blood-sparing effects but impairs surgical field quality.